2-Arylbenzofuran, Flavonoid, and Tyrosinase Inhibitory Constituents of Morus yunnanensis

Two novel 2-arylbenzofuran dimers, morusyunnansins A and B (1 and 2), two new biflavonoids, morusyunnansins C and D (3 and 4), two new flavans, morusyunnansins E and F (5 and 6), and four known flavans (7-10) were isolated from the leaves of Morus yunnanensis. Compounds 5-8 showed potent inhibitory effects on mushroom tyrosinase with IC50 values ranging from 0.12 +/- 0.02 to 1.43 +/- 0.43 mu M.